Then the poor inventor had to begin again and make another machine, to prove to the officials in the Patent Office that the cotton-gin was his invention, before they could make out for him the patent right, which said he was the only person allowed to make and sell that machine in the United States. Before he could get this patent he found that others were making, selling, and trying to get a patent for machines made like the stolen pattern.
Young Whitney’s friend Miller furnished him money, not only to secure his patent rights and make the machines, but to go into the courts and fight those who were trying to steal his rights as they had stolen his model. These people made him so much trouble and expense that it took thirteen years to beat them by lawsuits. A patent protected an inventor, by keeping others from making and selling that machine, for only fourteen years. When his rivals were beaten, Whitney had but one year left in which he and his friends could sell the machine so as to pay for all his time, labor, and expense. In that year he just made his cotton-gin pay for itself. But he had the great satisfaction of making the land in the southern states known as the cotton belt (because cotton could be grown in those states) worth hundreds of millions of dollars more than before. The raising of cotton grew to be such a great industry that negro slavery became more and more necessary in the cotton-growing states. So, without knowing it, Eli Whitney, by increasing the production of cotton, increased the number of black slaves in the south, and helped to cause the struggle for and against slavery, many years later. But as the inventor did not know that his cotton-gin would make slavery a curse to the United States, he was not to blame.
After his patent had run out and he could make no more money by selling his cotton-gins, Whitney got a government contract for the making of guns. He invented new machinery to make the parts of his guns and was the first to have each part made by a different man according to an exact pattern. When the parts were put together to make a complete gun no special fitting was necessary because each piece was exactly like every other piece for that same part. If a part of the gun was broken it could be replaced with a new one without any difficulty. Before that when one man made an entire gun all the parts were specially fitted and if one got broken a new one had to be made and fitted by hand, which took a long time and made repairs very expensive. His factories and the homes of his workmen formed a suburb of New Haven called Whitneyville.
Eli Whitney furnished hundreds of thousands of men with the weapons they used in putting down the slavery which his cotton-gin had been made the innocent cause of increasing.